In a wide variety of role playing games, a number of polyhedral dice are used. The commonest are in the shapes of the five Platonic solids.
Typically, these dice are referred to by the number of faces they have: a 'd6' is a regular cubic die, pronounced 'dee-six'.
Common Dice:
| Sides | Shape | Notes | Platonic |
|---|---|---|---|
| d4 | tetrahedron | Each face has three numbers: they are arranged such that the top number is the same on all three visible faces. | Yes |
| d6 | cube | A common die. Opposite faces must add to seven. | Yes |
| d8 | octahedron | Each face is triangular; looks something like two Egyptian pyramids attached at the base. | Yes |
| d10 | Irregular decahedron; see Dice/10-sided dice | Each face is kite-shaped; the smallest angle of five faces point to one edge, the smallest angle of the other points to the opposite. Not a regular polyhedron. Often, all odd number are on one half of the die and all even faces are on the other half. | No |
| d12 | dodecahedron | Each face is a regular pentagon. | Yes |
| d20 | icosahedron | Faces are equilateral triangles. Typically, opposite faces add to twenty-one. | Yes |
Uncommon Dice:
| Sides | Shape | Notes |
|---|---|---|
| d7 | A very uncommon die type, it's shaped as a pentagonal prism, thick enough to land either on its "edge" or "face". When landing on an edge, the topmost edge has pips for 1 through 5. The pentagonal faces are labeled with the digits 6 and 7. | |
| d30 | Each face is in the shape of a rhombus (diamond-shaped). | |
| d100 d% | Trade name: Zocchihedron | Usually modelled by rolling two d10, one labelled 00,10,20..90, the other normal. Examples do exist of 'true' d100's, but these are rare, and given the nickname death stars due to a passing resemblance to the Star Wars ship. Other d100s may be in the shape of a golf ball. |
Often the names of the dice appear in formulas for calculating game parameters: e.g., hit points. '6d8+10', for example, will yield a number between 16 (6×1+10) and 58 (6×8+10) with a bell curve distribution, as it means 'Roll an eight-sided die six times and add ten to the total of all the rolls'. Occasionally they may be written '10×d6+20' or '1d6×10+20'; this means 'roll one six-sided die. Multiply it by ten and add twenty', and avoids boring repetitive dice-rolling at the expense of generating a bell curve distribution.
